Do Congressman pay federal income taxes?

Yes of course. Basically no one - the President or Supreme Court Justices, etc...is exempted under the Tax laws because of their employment/employer. In fact, if anything all of these types are open to much more scruitiny, both officially as part of the requirments of their jobs, and unofficially...up to and including publically disclosing their returns and personal financial situations.

Frankly, I believe the people who spread and promote such nonsense (it is a never ending selection of whio gets treated specially) are not only ignorant, but perhaps doing so with some intent to cause discontent and hate among the populace. Maybe they are commie pinkos? Or just anti-American traitors. Something like that at least...spreading vicious lies about the leaders and defenders of the country.